that 273 at .060 over, is now a 283.6, rounds to 284/ 4.65liters.
The bore is 3.69. I don't think you can put a 2.02 in that hole, at any desirable lift.
A big-valve head is better-called a big-port head, which comes with either 2.02s or 1.88s .
IMO, and that's all it is; I'd rather use an intake valve that doesn't get shrouded at a higher lift, than a shrouded big valve at a more normal lift. With the advent of 1.6 arms, it's easy to get up over .500 lift.
But I also can't see a good reason to run big-port heads on your 284, for your street application.